1. Field of the Invention
The invention relates in general to needles with modified tips used for example in spinal injections, and specifically to a method of retaining a tip protector for such a needle.
2. Description of the Related Art
Historically in the medical field, needles have been necessary in many procedures. Unfortunately the danger of accidental injury by needles has increased due to the risk of transmission of various blood borne diseases such as AIDS and Hepatitis. In many procedures the use of needles has been reduced or eliminated, but there remain many situations in which the use of a needle is unavoidable. In these cases, it is desirable to limit the danger of accidental injury to people by the needle as much as possible.
One such situation in which use of a needle has not been eliminated is the insertion of catheters into a patient""s vein. The catheter is inserted into a patient""s vein by a health care worker by using a handheld placement device which includes a sharp-tipped needle. The needle is positioned in the interior hollow portion of the catheter with its tip extending slightly beyond the edge of the catheter. The opposite end of the needle is connected to a hub which is capable of being held by the health care worker.
Once the catheter has been inserted into the vein of the patient, the needle is withdrawn, leaving the catheter in the patient""s vein. Once the needle has been removed from the catheter, however, the sharp tip of the needle is exposed, and poses a threat to anyone who handles it thereafter. With the needle tip exposed, the health care worker or anyone else who handles the needle is in danger of being accidentally pricked by the needle, and possibly infected with any blood-borne diseases the patient may have been carrying.
Bent needles such as Huber, Husted, and Touhy needles may be used with similar catheters in procedures such as the injection of spinal anesthetics where it is desirable to keep tissue from being cored and jammed in the hollow tip of the needle. These needles are often used in conjunction with stylets which are inserted into the needle and block the opening in order to further help keep tissue from jamming the needle. The stylet is a thin, flexible rod with a tip shaped such that it provides a flat surface at the opening of the needle. A hub at the end opposite the tip may be grasped and used to remove the stylet from the hollow interior of the Huber or other needle.
Many tip protectors have been developed for straight catheter needles. One in particular as described in patent publication WO 99/08742 (also U.S. application Ser. No. 08/097,170) to Wynkoop et al. describes a tip protector commercially referred to as the xe2x80x9cBraun clip.xe2x80x9d The Braun clip was developed for use with over-the-needle intra-venous catheters as described above. This particular device is adapted to fit within the hub of the catheter such that when the needle is withdrawn from inside the catheter, the Braun clip slides toward the sharp tip until it reaches a retaining element which holds the clip from sliding completely off the tip. The retaining element is positioned to stop the clip such that its shielding portion covers the sharp tip of the needle.
When used with a typical I.V. catheter needle, the Braun clip is retained from sliding off the end of the needle by crimping the needle near the sharp tip. Unfortunately, needles such as the Huber which are often used in conjunction with stylets cannot be crimped due to the need for free movement of the stylet within the space inside the hollow needle. Thus, it is desirable to have a method of retaining a tip protector on a needle with a bent tip such as a Huber needle.
It is therefore an object of the present invention to provide a method of retaining a tip protector on a needle with a bent or otherwise modified tip which does not involve crimping or otherwise altering the profile of the needle.
The present invention employs a tip protector device having a protector portion and a portion that slides on the needle but cannot slide past the needle bend and stops the protector portion in the desired protective position. In the present invention a preferred form of the slide portion includes a sleeve with an internal diameter slightly larger than the needle""s outer diameter. The sleeve slides freely over the majority of the needle shaft, but not around the needle bend and off the end of the tip. The protector portion can be of a known clip type such as the Braun clip.
The length of the sleeve is also an important dimension. It should be such that the Braun clip is allowed to operate properly without falling off the end of the tip. If the sleeve is too long, the clip will be restrained from closing over the needle tip. If the sleeve is too short, it may slide around the bend and off the tip. The details of these dimensions and relationships are expanded in the detailed description below.
One advantage of the use of a sleeve as described herein is its ease of assembly. Once the sleeve has been properly sized, it can be easily slid onto the shaft of the needle in operative relationship with the Braun clip before attaching the needle hub or before bending the tip. Another advantage is the low cost of the part. A sleeve providing features and advantages of the present invention can be produced very economically.
When used with an over-the-needle catheter, the tip protector and the sleeve can initially be conveniently housed in a rear hub on the catheter.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed.